1. Field of the Invention
The present invention relates to a camera, more particularly to a camera system to which interchangeable lenses or accessories can be detachably attached.
2. Description of the Related Art
In a camera system to which interchangeable lenses or accessories can be detachably attached, the camera main body generally performs various calculations and controls based on information from the interchangeable lenses or the camera accessories.
For example, in Japanese Patent Publication No. 5-59411, a technology is disclosed in which various types of data required for an automatic focus operation or an exposure operation are stored beforehand in a ROM of a lens. When the camera main body is operated, the camera main body communicates with the interchangeable lens to read out the data stored in the ROM.
Moreover, in Japanese Patent No. 2868226, a technology is disclosed in which all the data stored in an interchangeable lens are read out to memorize the data in memory means in a camera main body at a time when the interchangeable lens is attached or a power supply is turned on.